Practical plasma arrester

ABSTRACT

The present invention relates to practical plasma. Because in the plasma lightning arrester of the prior art, the intensity of the balancing charge is usually insufficient and disappear quickly, there is no sufficient time and intensity to balance out the induced charge on the surface of object to be protected, therefore the plasma lightning arrester of the prior art can not prevent the object from lightning strike effectively. The present invention appends a RC charging-discharging circuit on the passage way of balancing charge in series, so that the passing period of balancing charge is extended, and the lightning strike can be prevented effectively. The charge amplifier is arranged to intensify the balancing charge and enhance the protecting ability against lightning strike.

FIELD OF THE INVENTION

[0001] The present invention relates to a practical plasma arrester.More particularly, the present invention relates to a practical plasmaarrester in which an device for amplifying and slowly releasing thebalancing charge is used.

BACKGROUND OF THE INVENTION

[0002] The plasma lightningproof technology is a technology in which theplasma atmospheric layer is polarized by the lightning effect, and theinduced charge on the surface of the object to be protected is balancedout or weakened, so that the object can be protected from lightningstrike. The main structure is a conductive ball. The lower portion ofthe conductive ball is connected to an input of a charge amplifier, andthe output of the amplifier is connected to the surface of the object tobe protected through a wire. The underlying operating principle is: whenthe plasma gas is polarized by the electric field caused by thelightning precursor charge, the charge, which has the same polarity withthat of the precursor charge, enters into a charge amplifier from theconductive ball covered by the plasma, then further into the surface ofthe object to be protected, so as to balance out or weaken the inducedcharge on the surface of the object to be protected, therefore theatmosphere electric field on the surface of the object to be protecteddecreases in intensity, so that the electric field intensity can notrise to a value at which the atmosphere can be broken through,consequently the object to be protected can be protected from lightningstrike.

[0003] A charge amplifier is provided to enhance the protection abilityof the conductor covered by the plasma, so as to better protect theobject which is not covered by plasma.

[0004] When the lightning precursor charge develops to a lightningstrike level, the induced charge is produced, and the balancing chargeis produced, then the balancing charge flows into the surface of theobject to be protected, and the period of the above whole process isvery short, typically at the order of microsecond, but the danger periodof suffering from lightning strike is much longer, typically at theorder of 10□100 microsecond, therefore during the lightning strike, thebalancing charge for eliminating the lightning strike would disappearquickly, but at this time, the danger period has not finished yet, inother words, the possibility of suffering lightning strike still exists.Thus there is a need for the balancing charge to stay on the surface ofthe object to be protected for a longer time.

[0005] Further, there is also a need to modify the said charge amplifierso that it can be put into practical use for some special purpose.

OBJECTIVE OF THE INVENTION

[0006] The objective of the present invention is to provide a practicalplasma arrester wherein an device for amplifying and slowly releasingthe balancing charge is used. The plasma arrester of the presentinvention ensure that there is enough balancing charge to balance outthe induced charge on the surface of the object to be protected, so thatthe objet can be protected completely from lightning strike.

SUMMARY OF THE INVENTION

[0007] A practical plasma arrester in accordance with the presentinvention includes: a plasma, a conductor, a charge amplifier, a wire,characterized in that a practical charge amplifier and acharging-discharging circuit are respectively connected in series withthe conductor covered by the plasma and the wire connected with thesurface of an object to be protected, the said amplifier is arranged toenhance the protection ability of the conductor covered by the plasma soas to better protect the object which is not covered by plasma, the saidcharging-discharging circuit firstly stores the balancing charge afterthe balancing charge is amplified, then releases (i.e. discharges) thebalancing charge slowly, so that the stay period of the balancing chargeon the surface of the object to be protected can be extended.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008]FIG. 1 is a schematic view of the plasma arrester in the priorart;

[0009]FIG. 2 is a diagram of the charge amplifier in the plasma arresterin accordance with the present invention;

[0010]FIG. 3 is schematic view of the plasma arrester in accordance withthe present invention wherein an device for slowly releasing the chargeis appended.

DETAILED DESCRIPTION OF THE INVENTION

[0011] The practical plasma arrester in accordance with the presentinvention comprises, a plasma, a conductor, a charge amplifier, and awire, characterized in that a practical charge amplifier and acharging-discharging circuit are respectively connected in series withthe conductor covered by the plasma and the wire connected with thesurface of an object to be protected, the said amplifier is arranged toenhance the protection ability of the conductor covered by the plasma soas to better protect the object which is not covered by plasma, the saidcharging-discharging circuit firstly stores a balancing charge after thebalancing charge is amplified, then releases the balancing chargeslowly, so that the stay period of the balancing charge on the surfaceof the object to be protected is desirably prolonged.

[0012] According to the practical plasma arrester of the invention, thesaid charge amplifier includes a DC charging capacitor C1 for storingenergy, switch amplifiers, a device for polarity identifying andseparating, a high-frequency transformer, wherein the balancing chargeis connected to the input of the device for polarity identifying andseparating, one end of the output of the said device is connected to theinput of one switch amplifier, and another end of the output of the saiddevice is connected to the input of another switch amplifier, theoutputs of the two switch amplifiers are respectively connected to thetwo primary ends of the high-frequency transformer, the secondary endsof the high-frequency transformer are connected to the input of thecharging-discharging circuit, the DC power supply supplies charges thecapacitor to a rated value and supplies power for the switch amplifiersvia the central point between the two primary ends.

[0013] According to the practical plasma arrester of the invention, thedevice for polarity identifying and separating causes the inputtingcharge pulses with different polarity to flow into different switchamplifier; the said switch amplifiers may be opened or closed, and theoutputting amplitude of the switch amplifiers is proportional to thepulse amplitude of the inputting current pulse; the said DC power supplyhas small electric current and high voltage, it can charge the capacitorC1 to a rated value, typically at the level of 1 kV; the saidhigh-frequency transformer can raise the voltage that the amplifiers cantake on, typically at the level of 1 Kv, to a voltage of thecharging-discharging circuit which is desired by the user, typically atthe level of 10-100 kV.

[0014] According to the practical plasma arrester of the invention, thesaid switch amplifiers are electronic switches, the period of opening isproportional to the amplitude of the inputting electric current.

[0015] According to the practical plasma arrester of the invention, thesaid charging-discharging circuit is a device for slowly releasingcharge, and includes a resistor R and a capacitor C2 which is connectedin parallel with the secondary ends of the frequency transformer, oneend of the capacitor C2 is connected with the one end of the resistor R,the other end of the capacitor C2 is grounded, the other end of theresistor R is connected with the surface of the object to be protected.

[0016] According to the practical plasma arrester of the invention, thesaid charging-discharging circuit is a device for slowly releasingcharge, and includes three resistors and two capacitors, wherein acapacitor C2 is connected in parallel with the secondary ends of thefrequency transformer, one end of the capacitor C2 is connected with theone end of a resistor R1, the other end of the capacitor C2 is grounded,the other end of the resistor R1 is connected with the surface of theobject to be protected via a resistor R3 and a circuit with a resistorR2 and a capacitor C3 connected each other in parallel.

[0017] According to the practical plasma arrester of the invention, thesaid charge amplifier may be omitted when the object to be protected issmall, in other words, the conductor covered by the plasma is directlyconnected with the charging-discharging circuit. The invention will bedescribed in more detail with reference to the drawings.

[0018] The FIG. 1 is a schematic view of the plasma arrester in theprior art. As illustrated in FIG. 1, the precursor charge of thelightning strike is negative charge, the plasma 1 is polarized, thecharge on the outer surface of the plasma is positive charge, and thecharge inside of the plasma is negative charge, the negative chargeenters into the conductor so as to balance out the induced positivecharge therein. The charge which has the same polarity with the saidprecursor charge enters into the charge amplifier A to be amplified,then flows to the surface of the object 5 to be protected through a wire4 so as to balance out the induced positive charge therein. Whereas thepositive charge on the surface of the plasma disappears into theatmosphere. Because the induced charge on the surface to be protected isbalanced out or weakened, the electric field intensity on the surface ofthe object to be protected is decreased, so that the said electric fieldintensity can not reach the degree where the breakthrough would takeplace, as a result, the object to be protected can be protected fromlightning strike. Amplifier A connected with the wire 4 in series isdesigned to increase the balancing charge.

[0019] The FIG. 2 is a diagram of the charge amplifier A which is usedto enhance the protecting ability against lightning. The capacitor C1,which used to store energy, is charged to enough high voltage by the DCelectric power, then the capacitor can be used as the electric power ofthe switch amplifiers K1, K2. The inputting charge pulse flows throughthe device 2 for polarity identifying and separating, then flows throughthe actuator 3 or 4 depending on the different polarity, thereforeactuates the switch amplifier K1 or K2, after the charge is amplifiedthe charge pulse flows to the high-frequency transformer T so as to liftthe voltage.

[0020] The FIG. 3 is the schematic view of the practical plasma arresterin accordance with the present invention wherein the device B for slowlyreleasing charge is used. As illustrated in the figure, as soon as thelightning strike precursor charge reach the lightning strike level, thecapacitor C2 stores the balancing charge which is conducted from thewire 4, after the balancing charge disappears, the capacitor C2 cancontinue to release the charge to the surface of the object 5 to beprotected through the resistor R1, capacitor C3//resistor R2, resistorR3, so it can ensure that there is enough balancing charge during thedanger period of lightning strike, therefore the object 5 to beprotected can be protected from lightning strike. The function of thecapacitor C3 is to ensure that the surface of the object 5 to beprotected can be covered by the balancing charge at the beginning ofreleasing charge.

[0021] The values of the respective elements in the present embodimentare as follows: C1=5 μF, C2=0.1 μF, C3=2000 PF, R1=R3=1 KΩ, R2=10 KΩ,R=10 KΩ.

[0022] In the practical plasma arrester of the present invention, theconductor 2 covered by the plasma and the surface of the object 5 to beprotected are respectively connected with the charge amplifier A and thedevice B for slowly releasing charge, therefore, the balancing chargecan be stored after being amplified at the preliminary period of thelightning strike precursor charge reaching the lightning strike level,then the stored balancing charge is released slowly, in this way, thereleasing period of the balancing charge can be longer than thedangerous period of the lightning strike.

[0023] In addition, the said charge amplifier A can be omitted when theobject 5 to be protected is small, in other words, the conductor 2covered by the plasma is directly connected with the device B for slowlyreleasing charge.

[0024] In the practical plasma arrester in accordance with the presentinvention, because the said charge amplifier A and the device B forslowly releasing charge are used, when the lightning occurs, thebalancing charge, which has the opposite polarity, is induced by theprecursor charge, and the balancing charge flows into the device B forslowly releasing charge, and cause the capacitor connected in parallelbe charged immediately, after the balancing current disappears, thecharged capacitor supplies the balancing charge to the object to beprotected through the resistor connected in series, the period of thereleasing charge can be controlled to a desired length by appropriatelyselecting the values of the capacitors and the resistors. Therefore, theplasma arrester of the present invention can completely prevent theoccurring of the lightning strike.

[0025] The practical plasma arrester of the present invention can widelybe used in various occasions where an arrester is needed to preventlightning strike.

1. A practical plasma arrester, comprising, a plasma, a conductor, a charge amplifier, and a wire, characterized in that a practical charge amplifier and a charging-discharging circuit are respectively connected in series with the conductor covered by the plasma and the wire connected with the surface of an object to be protected, the said amplifier is arranged to enhance the protection ability of the conductor covered by the plasma so as to better protect the object which is not covered by plasma, the said charging-discharging circuit firstly stores a balancing charge after the balancing charge is amplified, then releases the balancing charge slowly, so that the stay period of the balancing charge on the surface of the object to be protected is desirably prolonged.
 2. The practical plasma arrester of claim 1 wherein the said charge amplifier includes a DC charging capacitor C1 for storing energy, switch amplifiers, a device for polarity identifying and separating, a high-frequency transformer, wherein the balancing charge is connected to the input of the device for polarity identifying and separating, one end of the output of the said device is connected to the input of one switch amplifier, and another end of the output of the said device is connected to the input of another switch amplifier, the outputs of the two switch amplifiers are respectively connected to the two primary ends of the high-frequency transformer, the secondary ends of the high-frequency transformer are connected to the input of the charging-discharging circuit, the DC power supply supplies charges the capacitor to a rated value and supplies power for the switch amplifiers via the central point between the two primary ends.
 3. The practical plasma arrester of claim 2 wherein the device for polarity identifying and separating causes the inputting charge pulses with different polarity to flow into different switch amplifier; the said switch amplifiers may be opened or closed, and the outputting amplitude of the switch amplifiers is proportional to the pulse amplitude of the inputting current pulse; the said DC power supply has small electric current and high voltage, it can charge the capacitor C1 to a rated value, typically at the level of 1 kV; the said high-frequency transformer can raise the voltage that the amplifiers can take on, typically at the level of 1 Kv, to a voltage of the charging-discharging circuit which is desired by the user, typically at the level of 10-100 kV.
 4. The practical plasma arrester of claim 2 wherein the said switch amplifiers are electronic switches, the period of opening is proportional to the amplitude of the inputting electric current.
 5. The practical plasma arrester of claim 1 wherein the said charging-discharging circuit is a device for slowly releasing charge, and includes a resistor (R) and a capacitor (C2) which is connected in parallel with the secondary ends of the frequency transformer, one end of the capacitor (C2) is connected with the one end of the resistor (R), the other end of the capacitor (C2) is grounded, the other end of the resistor (R) is connected with the surface of the object to be protected.
 6. The practical plasma arrester of claim 1 wherein the said charging-discharging circuit is a device for slowly releasing charge, and includes three resistors and two capacitors, wherein a capacitor (C2) is connected in parallel with the secondary ends of the frequency transformer, one end of the capacitor (C2) is connected with the one end of a resistor (R1), the other end of the capacitor (C2) is grounded, the other end of the resistor (R1) is connected with the surface of the object to be protected via a resistor (R3) and a circuit with a resistor (R2) and a capacitor (C3) connected each other in parallel.
 7. The practical plasma arrester of claim 1 wherein the said charge amplifier may be omitted when the object to be protected is small, in other words, the conductor covered by the plasma is directly connected with the charging-discharging circuit. 